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2 Sheets-Sheet I.

(No Model.)

G. R. BABBITT. GUT-OFF VALVE GEAR.

Patented Nov. 4, 1890.

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(No Model.) 2 Sheets-Sheet 2,

G. R. BABBITT. OUT-OFF VALVE GEAR.

No. 439,619. Patented Nov. 4,1890.

NI TNESEES. I INVENTDR.

UNITED STATES PATENT OFFICE.

GEORGE R. BABBITT, OF PROVIDENCE, RHODE ISLAND.

CUT-OFF-VALVE GEAR.

SPECIFICATION forming part of Letters Patent No. 439,619, dated November 4, 1890.

Application filed August 13, 1889- Serial No. 320,584- (No model.)

To all whom it may concern: 1

Be it known that I, GEORGE E. BABBITT, a citizen of the United States, residing at Providence, in the county of Providence and Stateof Rhode Island, have invented certain new and useful Improvements in Out-Off-Valve Gears; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it apperta'ins to make and use the same. reference being had to the accompanying drawings, and to letters of reference marken thereon, which form a part of this specification.

In engines provided with independent steam and exhaust valves and having liberating valve-gear adapted to automatically cut off the steam from the cylinder at any point of the pistons stroke it is very essential that the latch, which is pivoted to the operatingarm, particularly in the Corliss type of engines, be constructed so as to engage the valve arm or lever and the tripping-cam actuated by the governor with the least possible friction. It is desirable also that the surfaces of the tripping mechanism or hooks which are subjected to the most wear be so constructed and arranged that they may be readily renewed.

Another essential feature is that the steamvalves be positively closed each time after being unhooked and prior to being hooked on again. Still another desirable addition to a cut-off engine is that in case the governorbelt or operating mechanism becomes broken or otherwise inoperative, thus permitting the engine to race, that a counteract-ing device be employed to automatically prevent the hooking on of the valve as in opening.

My invention herewith combines in a liberating valve-gear an operating-arm having a gravity operating latch pivoted thereto. The outer or working face of the arm of the latch is convex and adapted to automatically engage the lower inner edge of the square steel catch loosely mounted on the bolt of the valve-stem arm by gravity, as stated; or, in other words, the hook is located between the center of the valve-stem arm and the center of the drop-rod pivoted at the outer end of said arm. The latch is preferably provided with a loosely-m ounted roll, which, in con 3' unc- -tion with a tripping-cam mounted to vibrate in unison with the fluctuations of the governor, serves (with the moving arm) to unhook the valve, thereby cutting off the live steam from the piston. Another portion of said cam serves to prevent the vibrating latch from hooking on and opening the valve in case the governor becomes inoperative.

The invention further consists of a device for positively closing the valve and an arrangement whereby the hook-surfaces may be readily renewed as they become worn by @011- stant use, all as will be more fully hereinafter set forth and claimed.

Heretofore, so far as I am aware, the latch has been so constructed and mounted that it engages the outer portion of the hooks surface that is, the edge farthest from the center of the valve-stemthe contact being effected by the use of one or more springs. Such construction which depends upon a spring for hooking on obviously is open to objections. Moreover, the action of the knock-off of the governor upon the latch, as in cutting off, is dependent upon said spring. Heretofore also the relations of the drop-rod and hook have been such that the work of lifting the dash-pot piston or plunger was borne almost wholly by the valve-stem itself.

The object of my invention, in the main, is to overcome the objection or disadvantages above referred to. To this end I utilize the weight of the latch itself in hooking on, the same being so mounted that its engagement with the valve-arm is assured and maintained until released by the knock-off.

Another advantage of my construction is that the work of lifting the plunger is borne by the hook-pin of the operating-lever, thereby largely relieving the valve stem. By means of my improvement the steam entering the cylinder is out off by the inner edge of the valve instead of the outer edge, as common, the steam thereby passing direct into the cylinder with the least amount of friction or resistance.

In the accompanying two sheets of drawings illustrating my improvement-s, Figure 1, Sheet 1, represents an end view thereof, corresponding to the back end steam-valve, the parts being connected and moving to uncover the port, a part of the valve-stem arm being omitted. Fig. 2 isa plan view. Fig. 33, Sheet 2, is an end view in partial section, showing the latch in engagement with the knock-oil' or tripping-cam, thereby releasing the valvearm, omitted from this figure, and permitting the d rop-rod to fall and close the valve. Fig. 4 is a partial sectional view taken through m not Fig. 1. Fig. 5 is a reduced side view in elevation showing a Corliss cylinder pro- Vided with my improvements; and Fig. (i is a cross-sectional view through one of the steamports and valve, showing the direct manner in which the steam enters the cylinder.

The following is. a more detailed description of my invention, including the manner of its operation: a, again referring to the drawings, designates the valve-arm, the same being rigidly secured to the valve'stem s, as usual in this type of engine. In the outer end of the arm is mounted a bolt or steel pin a, which projects from either side thereof, the front portion of said pin having the drop-rod v mounted thereon. The d rop-rod is adapted to be connected with a weight or vacuum-pot, and serves in falling to close the steam-valve, also as common. The rear portion of thepin is provided with a loosely-mounted square sleeve or catch a of steel, as clearly shown in Figs. 3 and i. This sleeve and head portion also forms a part of the hook in combination with a latch A, about to be described. It will readily be seen that when the corners oredges of the catch it become worn it may be turned ninety degrees on its axis, thereby presenting a new surface to engage the latch, and so on until the four edges have been used, after which the catch may be used a-similar period by removing it from the' pin and reversing it, thus presenting anew series of surfaces to the hooks action.

1) indicates the operating lever mounted upon the hub 72, Fig. 2, of the valvestem bonnet, as usual. One portion of said lever is provided with a pin 15, as common, on which is mounted a connection or link cl, which in turn is connected to and actuated by the loosely-mounted wrist-plate to, Fig. 5, the latter being adapted to be vibrated on its pin or center 0 by means of a pin 1), also as usual. The other arm of the operating-lever carries a pin or stud 2. The radius of this part of the lever is preferably somewhat less than that of the valve-arm a.

A designates the latch or tripping-lever pivoted on the said pin 25. The latch-leveris provided with two arms '1" T The latter arm extends inwardly toward the center of the valve-stem s, and is provided with a looselymounted roll 0' at its free end. The other arm 7' is made considerably longer than the arm 9' and is provided with a convex working-surface 0". This curved portion of the lever lies adjacent to the inner vertical face of the catch a, before described. A notch or is formed in the arm rat the upper termination of the convex surface r, into which is loosely fitted the curved faced head to of a steel bolt to. (See Fig. 3, the.) The upper edge of the bolt-head forms a shoulder or seat 11/, adapted to engage with the catch it. It will be noticed that the head to is made substantially square, thereby adaptingthe bolt to be turned one hundred and eighty degrees to present a new wearing-stnface. The latch A is constructed and mounted so as to hook on by gravity.

fdesignates an arm orleverloosely mounted upon the outer end portion of the valve-stem bonncts hub and intermediate of the two levers a and I), (see Fig. 2,) the arm f being connected by a rod 6 to the governor. The relative positions of this arm to the latch-lever, &c., in working obviously correspond with and are dependent upon the action of the governor, as usual. The hub of the arm is provided with a raised band on, which is cut away at its upper side to form the two cams or knock-offs m m, the former being arranged to control the point of cut-off within its range. By means of this arrangement, in conjunction with the freely-turning roll 7', engaging the cams, the work imposed upon the governor, as in cutting off, is greatly reduced. The other or stop-motion cam m is located radially to the rear of the former cam, so that in case the governor-belt breaks the action of the governor, as in coming to a state of rest, will bring the cam on forward a distance sufficient to prevent the latch in its vibrations from hooking on to open the steam- Valve.

B indicates a Corliss cylinder of usual form provided with two steam-valves, from which extend the stems or rods .9 3', each having a valve-arm a secured thereto. The exhaust-valves are operated by the two links d, each being connected to an arm a, secured to the outer end of the stem .9. The wristplate 10 is mounted to vibrate on the wristpin 0. A fixed pin c ,arranged in said wristplate and common to both links d, serves to transmit an oscillating movement to the exhaust-valve, as common. A similar pin 0, in connection with links (1, performs a like oflice to the operating-levers I). Now, assuming the wrist-plate to be moving in the arrow-direction, the arm Z), (at the back end of cylinder,) with its latch A, already hooked onto the valve-arm a through the medium of the catch a, uncovers the stcanrport. In case the cutoff is effected by the action of the governor, the roll 0' of the latch will revolve in the depressed circular path or hub of the arm f until it meets the cut-off lug m, in passing over which the lower arm 1' of the latch is forced from the catch. The drop-rod o, jointed to the valve-arm, in falling instantly closes the steam-port, the same remaining closed until a reverse movement of the wrist-plate, &c., brings the latch again in position to hook onto the valve-arm to repeat the operation. During the action of the releasing mechanism just described the exhaust-port at the opposite end of the cylinder is uncovered, as usual. In case the rod 0 does not drop sufficiently to effect a complete closing of the steam-port, owing to accidental causes, then the under side n of the eye or hub of the latch on its return stroke will engage the upper side of the catch and force the valve-arm downwardly to its limit, thereby positively closing the port. During the latter movement the shoulder n is automatically vibrated under the lower edge of said catch by gravity, so that when the operating-lever is next moved upwardly it will uncover the port. This arrangement, it will be seen, constitutes a positive closing device at all times. By means of this manner of constructing and mounting the latch, &c., the steam passes directly from the steam-chest 0 through the port 9 to the cylinder, as shown in Fig. 6, whereas in engines of this type as usually made the steam is forced to pass from the chest over the valve and to enter the cylinder from the opposite side, thereby reducing the efficiency of the steam to an appreciable degree.

It is evident that the roll 'I', mounted in the end of the latch, may be dispensed with and the arm itself be adapted to engage the cams m 'm'. I prefer the former arrangement, however, as working with less friction.

In applying my improvement to a vertical engine it is obvious that the operating-lever I) need have but one arm, as the connection d can be jointed direct to the pin it, the latter of course being slightly modified for the purpose.

I claim as my invention 1. The combination, with the looselyrnounted operating-lever and the catch-carrying automatically-dropping valve-arm secured to the valve-rod, of the gravity-acting latch-lever jointed to the operating-lever and adapted to engage said catch, and provided at its outer or free end with a loosely-mounted roll 1', and a governor-controlled cam loosely mounted concentrically with said valve-rod and arranged to engage said roll, substantially as hereinbefore described, and for the purpose set forth.

2. In a cut-ofi-valve gear, the combination of a pivotedly mounted counterweighted governor-tripped latch-lever traveling in unison with the wrist-plate, and provided with a depending arm having a convex face in which a notch or hook is formed, and a mounted valve-arm having at its free end a drop-rod and catch, the inner face of the latter arranged to engage the notch formed in the latch-lever, substantially as hereinbefore described and set forth.

3. A cut-off-valve gear having a mounted vibrating governor-controlled loosely-pivoted latch-lever A, arranged to hook on by gravity, and having the hook portion of said lever located and vibrating between the center of the valve-stem and the inner side or face of the catch u, substantially as hereinbefore set forth.

In testimony whereof lhave aflixed my signature in presence of two Witnesses.

GEORGE R. BABBITT.

Witnesses:

CHARLES HANNIGAN, GEO. H. REMINGTON. 

